Infections with respiratory tract viruses are known triggers of wheezy episodes in children. Infection rates have been reported between 62-95% during these wheezy episodes. The most common viruses are rhinovirus, respiratory syncytial virus (RSV) and coronavirus during wheezy episodes. A most recent study looked into these wheezy episodes to determine their viral or bacterial trigger and to see if they affected the duration of the wheezy episodes. A wheezy episode was defined as 3 consecutive days during which the child had wheezing symptoms. 283 children were studied in their first 3 years of life.
The results showed rhinovirus, RSV and coronavirus were tested a high amount in the samples, as expected because we have always known that viruses play a role in wheezy episodes. But the bacteria, S pneumoniae, M catarrhalis and H inluenzae were also found in a high amount of samples. In only 5%, no pathogen was found. RSV exhibited a marked peak during the winter months, whereas all other viruses and bacteria were found throughout the year. During the summer month, a large percentage of samples had no pathogen.
The median duration of wheezy episodes was 9 days. There was no difference in duration of wheezy episodes associated with any specific viral or bacterial trigger. No species caused more sustained symptoms than others.
Pathogenic bacteria were more common than viruses during wheezy episodes, and hence the term viral wheeze should be abandoned because both viruses and bacterial infections are triggers of wheezy episodes in young children.
The results suggest that although microbiological pathogens act as instigators of respiratory disease in children, other factors determine the duration of the symptomatic episode, such as allergic sensitization and an altered immune response. It has been suggested that deficiencies in antiviral activity and integrity of the airway barrier might make asthmatic patients more likely to have severe viral respiratory tract infections of the lower airway.
The key messages are the duration of wheezy episodes in young children is independent of the specific viral or bacterial triggers. And that bacteria infections play a large role in childhood wheezy episodes than we thought before and it deserves more attention than the current narrow focus on viruses.
If your young child is experiencing wheezy episodes, you should contact your pediatrician or pediatric allergist to help you manage his/her symptoms. A pediatric allergist is a physician who completed a pediatric residency and an allergy and immunology fellowship.